June 25, 2005

Smoking, Attention, & Memory in Schizophrenia

In the past, we've covered the topic of schizophrenia and nicotine: See Schizophrenia and Nicotine Study and A Surprising Twist, Nicotine as Treatment. A new study which also investigates this topic and which was "funded by grants from from The National Institute on Drug Abuse and the National Alliance for Research on Schizophrenia and Depression" suggests that nicotine may help improve "attention and short-term memory" in people suffering from schizophrenia. The researchers involved with the study claim that "people with schizophrenia smoke two to three times more than smokers without (brain disorders)." Researchers discovered that when participants suffering from schizophrenia stopped smoking, their attention and short-term memory were negatively affected. But, when the same participants started smoking again, "their cognitive function improved." Further, "...no effects from stopping or resuming smoking were observed in smokers without (brain disorders)."

Participants with and without schizophrenia were then asked to smoke while taking a drug called mecamylamine, which blocks nicotinic acetylcholine receptors in the brain, preventing the nicotine from acting on those receptors. Mecamylamine blocked the ability of smoking to improve cognitive deficits in schizophrenia, but not in persons without mental illness. The findings suggest that when people with schizophrenia smoke, they may in part be self-medicating with nicotine to remedy cognitive deficits. "Our findings have significant implications for developing treatments for cognitive deficits and nicotine addiction in schizophrenia," said Kristi Sacco, associate research scientist in the Department of Psychiatry (Yale University) and first author of the study. She said the results may also help explain the high rates of smoking in people with schizophrenia. She added that this study does not suggest that people with schizophrenia who do not smoke should start smoking.